Speed of Retraction of Rubber

1945 ◽  
Vol 18 (2) ◽  
pp. 380-393
Author(s):  
R. B. Stambaugh ◽  
Margaret Rohner ◽  
S. D. Gehman
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Standard Test ◽  
Practical Application

Abstract The results obtained with this apparatus show that interesting information can be obtained by making measurements of the speed of retraction under various conditions and by comparing different compounds and polymers. This information should be of value both for a better understanding of the molecular structure and the forces involved and also as a practical means for properly qualifying the material as to its elastic properties. The device appears to have an immediate practical application as an aid to the compounder in determining the “best” cure. The apparatus is quite simple to use and if properly designed is sturdy and dependable. Reliable measurements could be made at the rate of about fifty per hour without requiring much skill. Thus, the speed of retraction measurement would be practical for a routine, standard test.

The Oil Resistance of Rubber. I Study of the Swelling of Vulcanized Rubber

1936 ◽  
Vol 9 (1) ◽  
pp. 70-73
Author(s):  
Yoshio Tanaka ◽  
Shû Kambara ◽  
Jirô Noto
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Mixed Solvents ◽  
Experimental Results ◽  
Stress Strain ◽  
Oil Resistance ◽  
Effect Of Solvents ◽  
Vulcanized Rubber

Abstract To study the effect of solvents on the elastic properties of vulcanized rubber, the following three points were investigated. 1. The swelling maximum obtained by various mixed solvents. 2. The stress-strain curves of rubber swollen to different degrees. 3. Time-swelling and time-deswelling curves. The spiral theory of molecular structure of rubber proposed by Fikentscher and Mark is utilized to explain the experimental results.

scholarly journals IV. The molecular structure and elastic properties of the biological cells

1938 ◽  
Vol 166 (924) ◽  
pp. 76-96 ◽  
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Elastic Behaviour ◽  
Biological Cells ◽  
Structural Elements ◽  
Cortical Cells ◽  
Histological Features ◽  
X Ray ◽  
Different Types ◽  
Keratin Fibres

Amongst the difficulties encountered in the study of the structure of hair not the least is its heterogeneity, whether considered crystallographically or histologically. From the former viewpoint progress has been made possible by assuming that there is no clear demarcation between “crystalline” and “amorphous” keratin, but rather that there is a continuous gradation of organization, so that the properties of “crystalline” keratin, which lies at one end of the scale, may be linked by a series of almost imperceptible changes with those of the keratin of any other degree of regularity. The X-ray photographs of the better organized parts have been regarded as signposts pointing the way to an understanding of what is happening, in the molecular sense, in the rest of the fibre substance. Histologically, it is possible to define to a certain extent the part played by the various structural elements by comparing the properties of different types of hair. In this way we find that all hairs have certain basic similarities in their behaviour, and if we confine our attention to these we may at once eliminate, as being of no fundamental importance, such special histological features as the cuticle or the medulla, which occur in certain types of hair only, or can be removed from the specimen. There remains, as the seat of the characteristic properties of keratin fibres, only the cortex, which in all hairs consists of a mass of biological cells apparently fused together by an “intercellular medium”. The present work is an attempt to discriminate between the cortical cells and the intercellular material in their relation to the elastic behaviour of the fibre.

Multiscale Modeling Techniques Based on Molecular Structure and Elastic Properties

2013 ◽  
Vol 312 ◽  
pp. 438-441
Author(s):  
Jiu Li
Keyword(s):  
Molecular Structure ◽  
Force Field ◽  
Elastic Properties ◽  
Polymer Structure ◽  
Structure And Properties ◽  
Basic Principles ◽  
Multi Scale ◽  
Scale Modeling ◽  
Modeling Techniques ◽  
Nonlinear Continuum

Based on the principle of using atomistic force field, and the use of ultra-flexible multi-scale modeling techniques to predict the polycarbonate and polyimide polymer molecular structure and the elastic properties of the system. The model combines molecular modeling and nonlinear continuum mechanics basic principles, to simulate and predict the behavior of the material properties of the polymer molecular structure. For the polymer structure and properties, using a plurality of force field simulation to predict the contrast, and binding experiments measured polymer performance value, using static and dynamic molecular simulation technology for molecular mechanics energy minimization to solve.

scholarly journals X-Ray studies of the structure of hair, wool, and related fibres. II.- the molecular structure and elastic properties of hair keratin

1933 ◽  
Vol 232 (707-720) ◽  
pp. 333-394 ◽  
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Historical Development ◽  
Complex Nature ◽  
X Ray ◽  
Hair Keratin ◽  
Structural Principles ◽  
Series Of Experiments ◽  
The Subject ◽  
Ray Methods

In a previous communication* an account was given of a preliminary exploration, chiefly by X-ray methods, of the problem of the molecular structure of animal hairs. The present paper is a natural continuation of the record, in which earlier tentative suggestions are either confirmed or rejected, and an attempt is made to lay bare the general structural principles underlying the properties of the protein, keratin . It will be unnecessary here to outline once more the historical development of the subject; we shall proceed at once to the main point of this introductory section, which is to give what appears to be the solution of the problem before setting out in detail the experimental facts and arguments leading up to it. Such a procedure is advisable because of the complex nature of the properties under discussion ; such a long series of experiments have been involved in their elucidation, that without some sort of preliminary statement of the chief conclusions, the issue is apt to grow confused.

Co-curing of epoxy resins with aminated lignins: insights into the role of lignin homo crosslinking during lignin amination on the elastic properties

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Marcus W. Ott ◽  
Christian Dietz ◽  
Simon Trosien ◽  
Sabrina Mehlhase ◽  
Martin J. Bitsch ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Nanometer Scale ◽  
Predominant Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Flexural Tests ◽  
The Relationship ◽  
Elastic Modules

AbstractTo improve the reactivity of lignin for incorporation into high value polymers, the introduction of amines via Mannich reaction is a commonly used strategy. During this functionalization reaction, intra- as well as intermolecular lignin–lignin crosslinking occurs, which can vastly change the elastic properties of the lignin, and therefore, the properties of the resulting polymer. Therefore, the molecular structure of the amine that is used for such a lignin functionalization may be of great importance. However, the relationship between the molecular structure of the amine and the elastic properties of the lignin-based polymer that is generated thereof, has not been fully understood. Herein, this relationship was investigated in detail and it was observed that the molecular flexibility of the amines plays a predominant role: The use of more flexible amines results in an increase in elasticity and the use of less flexible amines yields more rigid resin material. In addition to the macroscopic 3-point bending flexural tests, the elastic modules of the resins were determined on the nanometer scale by using atomic force microscopy (AFM) in the PeakForce tapping modus. Thus, it could be demonstrated that the intrinsic elasticities of the lignin domains are the main reason for the observed tendency.

scholarly journals X -ray studies of the molecular structure of myosin

1940 ◽  
Vol 129 (856) ◽  
pp. 307-332 ◽  
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Polypeptide Chain ◽  
Molecular Configuration ◽  
X Ray ◽  
Chain System ◽  
The Cross

The X-ray and elastic properties of myosin are found to resemble most closely, not those of natural keratin, but those of keratin that has suffered breakdown among the cross-linkages (including disulphide bridges) of the polypeptide grid. The supercontraction of myosin cannot be explained as due simply to disorientation of long thin units: it must involve a further folding of the polypeptide chain system. The fact that myosin and keratin are similar in both molecular configuration and elastic properties is discussed in the light of recent X-ray and chemical findings, and the X-ray interpretation is given of the denaturation of myosin.

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